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Applied Physics Colloquium Precursor Structures in Crystallization/Precipitation Processes Jens Rieger BASF Advanced Research Initiative 4:00 pm, February 29 refreshments start at 3:30 pm 209 Pierce Hall Harvard University Abstract: Crystallization of inorganic (and organic) matter often proceeds via intermediate stages – rather than by simple nucleation and growth mechanisms (1). Recent time-resolved studies on the structural evolution of precipitating CaCO3 obtained by means of X-ray microscopy and quench cryo-transmission electron microscopy will be presented, emphasizing the role of precursor structures that not only comprise crystal modifications that are less stable than the final one (Ostwald’s rule of stages), but also amorphous, hydrated (nano-) particles and emulsion-like precursors structures (2). The mode of action that water-soluble polymers play during the formation of calcium carbonate precursors and crystals will be discussed Naomi Brave Center Coordinator Nanoscale Science and Engineering Center School of Engineering and Applied Sciences Harvard University 29 Oxford Street Pierce Hall room 228 Cambridge, MA 02138 Tel (617) 495-1027 Fax (617) 495-9837 |